A tale written in Trinidadian Creole that was inspired by the true story of a family who cremated a baby in the wilds of the island, has been plucked from more than 5,000 entries to win the Commonwealth short story prize.

In Passage, Kevin Jared Hosein writes of a man who hears a story in a bar about a family living away from society, and sets out to find them. “A man is so small in the wilderness, believe me. The way how people is now, we ain’t tailored to live there. So when Stew say he stumble across a house in the middle of the mountain, my ears prick up. I take in every word as he describe it. A daub and wattle house in the middle of a clearing, walls slabbed with sticks and clay and dung and straw, topped with a thatch roof,” writes Hosein, in Trinidadian English Creole, a choice he had initially thought would put people off.

“Originally I was afraid – I didn’t think people would understand the Creole,” the Trinidadian author told the Guardian. But the novelist Sarah Hall, who chaired the award jury, said Passage was “immediately and uniformly admired by the judges”.

“It balances between formal language and demotic, ideas of civility and ferality, is tightly woven and suspenseful, beautifully and eerily atmospheric, and finally surprising,” said Hall. “It is, in essence, all a reader could want from the short story form; a truly crafted piece of fiction that transports the reader into another world, upends expectations, and questions the nature of narratives and narrative consequence.”

The annual prize is awarded to the best piece of unpublished short fiction from the Commonwealth. Stories can be submitted in Bengali, Chinese, English, Malay, Portuguese, Samoan, Swahili, and Tamil, with 5,182 stories entered from 48 countries this year.

Hosein, who received his £5,000 award in Cyprus on Wednesday night, first learned about the true story behind Passage when he was 15. “People were aware there was a family living along a trail – they had older living customs that wouldn’t be acceptable today. Their baby died, and they had a custom to send its spirit off by cremating the body. That is what drew attention to them, and the two parents were put in an asylum, and the older children into a foster home,” he said.

“The last thing on the news was that when the children were brought into society and saw a television, they couldn’t stop screaming. I remember it hanging in my head as a child for a long time. People just wrote it off as madness, but I thought it had more to it than that and I wanted to explore it.”

A science teacher as well as a writer, Hosein was a Caribbean regional winner for the Commonwealth prize in 2015. “Winning in 2015 was pure validation – I didn’t really put my writing out there before that,” he said. “But just the fact that I made it on to the shortlist told me that my work could resonate with people outside my region. You always have that doubt: ‘Am I really good?’”

This time, “I just felt pride – not just in me but in my country … There is not much opportunity in the Caribbean to make a name for yourself. I think the prize has helped with that,” he said.

Hosein is the author of three novels: The Beast of Kukuyo, which won him the Burt award for Caribbean literature, The Repenters, which was shortlisted for the Bocas prize, and Littletown Secrets.